Field of the Invention
The present invention relates to polymeric antimicrobial compositions. In particular the invention concerns novel antimicrobial ionomer compositions, methods of preparing the same and the uses thereof.
Description of Related Art
Antimicrobial technologies based on the bioactive properties of ionic silver are currently widely recognized as belonging to the most advanced solutions on the wide application field of antimicrobial materials both in the science community and the industries utilizing antimicrobial surface technologies. Ionic silver has a general status as a safe biocide in many applications. Also the wide antimicrobial spectrum of silver against most bacterial species, including the antibiotic resistant strains, e.g. MRSA and NDM-1 which currently generate a severe health treat to patients in the form of hospital infections, makes ionic silver particularly interesting.
Recently in the healthcare sector, strategies for improving hospital hygiene and preventing infections have been extended to cover the aspect of spreading of infections through various surfaces in the healthcare environments. Correspondingly the application of antimicrobial materials and coating technologies have been emphasized as a new complementary mean for together with other aspects contributing to the battle against hospital infections.
Multiple strategies have been utilized to form antimicrobially active, silver releasing surfaces on fibers and bulk material surfaces. Conventional strategies typically comprise attachment on the surfaces of silver containing particles, such as nanosilver, silver zeolite, silver zirconium phosphate and silver chloride containing titanium dioxide particles, by various chemical means, typically utilizing a carrier material. Another conventional method is to treat certain surface materials chemically in order to provide attachment of silver ions or silver containing particles on the surface.
Nanoparticulate silver (nanosilver) has recently been extensively studied emerged as a potentially hazardous material to health and environment, which again has increased pressure towards developing of new silver ion technologies
Liquid antimicrobial additives for liquid products, such as disinfection solutions, surfactants, paints, wax/polymer coatings, deodorizing solutions and cosmetic solutions, are typically based on utilization of silver citrate solutions or silver zeolite or particulate silver dispersions, colloidal silver.
To date, polymer carrier based silver technologies have not been studied or developed extensively. Technologies based on functional ionic polymers are rare.
International Published Patent Application WO2002/030204 discloses novel antibacterial agents, wherein the lone pair electrons of nitrogen atoms of amine compounds with high boiling point or water-soluble polymer with basic nitrogen at the backbone or side chain are coordinated with silver ion. Antibacterial and deodorizing solution comprising them are also disclosed.
US Published Patent Application No. 2009246258 discloses antimicrobial and odor adsorbing fabric substrate having a surface coating. The coating contains silver compounds and combination thereof, a hyperbranched polyethyleneimine derivative, potassium citrate, inorganic chloride, a polyurethane binder, and a cross-linking agent. The silver compounds are selected from the group consisting of silver zirconium phosphate, silver zeolite, silver glass, and any mixtures thereof or a conductive silver containing nanoparticles. ion-exchange resins, zeolites, or, possibly substituted glass compounds.
According to the publication hyperbranched polyethyleneimine derivative, abbreviated “h-PEI”, comprises at least one hyperbranched polyethyleneimine linked to one or more linear hydrocarbon groups having 5 to 30 carbons. The preferred silver containing compounds are silver zirconium phosphate available from Milliken & Company under the trade name ALPHASAN, silver zeolite available from Sinanen under the trade name ZEOMIC, and silver glass available from Ishizuka Glass under the trade name IONPURE. Inorganic chlorides are preferred, especially magnesium chloride and ammonium chloride. A range of ratios from 1:10 to 5:1 (chloride to silver ion). The h-PEI derivatives also suffered from discoloration and it was found that potassium citrate reduced or eliminated the yellowing of the h-PEI.